DxD: I'm Surrounded by Big Sister Devils!

Fallen angels, as their name implies, were once angels who had descended, losing the holy blessings granted by God and having their white wings tainted black.

Though they had fallen and been exiled from the heavenly ranks, fallen angels were not inherently devils. Unable to return to their angelic form, they became their own distinct faction.

According to historical records, a war erupted between heaven and hell a millennium ago, involving three major forces.

The first was the angels led by God, the second, the devils commanded by the Four Great Satans, and the third, the faction of fallen angels led by their governor.

The three factions clashed in a relentless struggle for world domination, fighting to the death!

However, what was initially thought to be an endless and devastating war that would leave no one standing, eventually ended in a rather anticlimactic manner.

The turning point was the abrupt intrusion of the Two Heavenly Dragons — the Red Dragon Emperor and the White Dragon Sovereign — into the battlefield. As the three factions were embroiled in their conflict, these dragons nonchalantly consumed the leaders of all three sides. Immediately after, they themselves became targets of the combined wrath of the three factions, being torn into countless fragments and even having their souls sealed away.

Once the disturbance caused by the dragons was dealt with, the three sides paused to assess the situation. Not only had they inflicted massive damage upon their enemies, but their own ranks were left severely depleted. It became clear that continuing the war would lead not to victory, but mutual annihilation.

Thus, the angel faction retreated, carrying their gravely injured deity back to Heaven to recover. The previous Satans had perished on the battlefield, leaving the devil faction in shambles. As for the fallen angels, they were nearly wiped out, with the survivors scattering to the winds.

This unexpected turn of events led to a three-way loss, leaving no victor in the struggle for supremacy.

The devils suffered the most severe losses. Not only was their leader lost, but the number of pure-blood demons dwindled to just a handful. Rias Gremory's family, the House of Gremory, was one of the few remaining pure-blood demon families that survived the war.

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"Still, it's strange. What are the fallen angels up to, showing up so suddenly now…?"

The scene shifted to the journey home after school. Fukuki stared at the setting sun, mulling over what Rias had mentioned earlier in the old school building.

Theoretically, while the devils suffered the greatest losses during the Great War, the fallen angels retained the smallest amount of overall power. With their already smaller numbers, the war's heavy toll left them with even less strength. Furthermore, their forces had scattered in disarray at the end of the war, making it difficult for them to regroup or rebuild.

"Emm... I really can't figure it out," Fukuki murmured.

One of his habits was to stop dwelling on unsolvable puzzles. For him, it didn't matter if someone was a devil or a fallen angel. As long as they didn't cause trouble in the human world, everything was fine. But if anyone insisted on stirring up chaos, they could expect to meet the same fate as a rogue devil he'd previously dealt with: deported to their next life.

"Forget it, let's head home—if I'm late again, Kuroka will throw a tantrum… Hmm?"

Just as Fukuki quickened his pace, a faint ripple of holy power in the air caught his attention.

It was like a drop of water falling into a calm lake, faint but perceptible. The sensation was somewhat similar to the domain expansion he'd felt with Saeko Senpai, but far less potent or malevolent. In fact, it felt immature and vaguely familiar. A barrier technique?

As someone born into the Keikain family of onmyōji, he was well-acquainted with such techniques. This was a simple warding barrier meant to keep people away.

Why would someone set up a barrier like this in such a place?

Fukuki's curiosity was piqued. Typically, warding barriers were used in cases where a practitioner detected traces of a malevolent spirit but couldn't immediately pinpoint its location in a large structure. By placing a ward around the area, they could prevent unrelated individuals from wandering in while conducting a search.

It was akin to police cordoning off a crime scene. But here, the building in question was a standalone residential home, not a large apartment complex or multi-story mansion. Searching it should have been straightforward, and Fukuki didn't sense any traces of malevolence.

Driven by curiosity, he changed his route, cutting through the residential area to trace the source of the holy power. To his surprise, the figure he saw was unexpectedly familiar.

It was none other than Asia, the golden-haired nun he had accidentally bumped into that morning.

The nun retained her gentle and kind demeanor, softly humming a tune as she focused on completing the final holy power infusion for the warding barrier in front of the house.

"Asia?" Fukuki called out, not bothering to conceal his presence as he approached.

Hearing her name, the nun froze momentarily, much like a startled rabbit. She lifted her head abruptly, her veil bouncing slightly with the motion. But her initial panic quickly transformed into delight as she recognized him.

"Oh, it's Mr. Fukuki. Are you on your way home from school? What a coincidence… um…"

Her voice trailed off abruptly as if she had just realized something important.

Then Asia blinked her emerald green eyes, her joyful smile gradually replaced by a hint of awkwardness.

"That means... my barrier failed, doesn't it? Since you're here, Fukuki-san?"

"No, you succeeded. It's just that, for certain reasons, barriers like this don't affect me," he reassured, walking closer and gesturing toward the house. "But, what are you doing here, Asia?"

"Oh, it's work!"

Talking about her job seemed to immediately revive Asia's earlier cheerfulness.

"Thanks to you helping me this morning, I safely arrived at the local church. The priest is currently exorcising a spirit inside, and since I couldn't be of much help, they let me handle the barrier outside."

"Exorcising?"

Fukuki tilted his head, his suspicions deepening. He hadn't sensed any malevolent presence in this residential area.

Could there actually be someone who understands exorcisms better than him, a true practitioner of the Keikain clan?

Sensing that something wasn't quite right, he sidestepped Asia and approached the house's front door. Gently pressing down on the handle, he pushed it open.

What greeted him was the suffocating stench of blood.